1. Field of the Invention
The invention relates to a laminating apparatus that covers and adheres the front and back surfaces of a laminate target, such as paper, using a sheet made of synthetic resin.
2. Description of Related Art
There has been known a laminating apparatus for laminating a medium, such as a card, by a sheet of synthetic resin film.
National Stage Laid-Open Patent Publication (KOUHYOU) No. 10-507005 based on a PCT application discloses an example of the laminating apparatus described above. In the laminating apparatus, a pair of sheet rolls which are wound around each sheet thereof for laminating both surfaces of paper are rotatably supported at upper and lower positions in a sheet cassette, and the sheet cassette can be detachably mounted to a sheet supply unit of the laminating apparatus.
In the laminating apparatus, a pair of upper and lower pinch rollers are disposed at the paper feed-out side of the sheet cassette. Both pinch rollers are structured so as to rotate in synchronization with a turn of an external handle.
Paper put on a paper supply tray is fed to the gap between the upper and lower sheet rolls, and the paper is sandwiched therebetween and laminated while drawing the upper and lower sheets. In this case, the sheet has an adhesive layer on one side thereof (pinching surface). A laminate thus formed is cut in an X direction (the direction perpendicular to a feed direction of the paper) using a cutter blade. Accordingly, the paper laminated by sheets of a PET film (laminate) can be obtained.
However, in the conventional apparatus, upper and lower sheet rolls are drawn from each periphery near a paper feed path between centers of rotation of the sheet rolls and are directly pinched at the pinch roller portion. Paper is fed to the pinching position, so that a pinch angle when the paper and the sheets are pinched by the pinch rollers (which is a contained angle formed by straight lines which connects the peripheries of each sheet roll and peripheries of the pinching side of the pinch rollers and the paper feed path) is small when the diameter of the sheet roll is large. The degree of the pinch angle increases as the diameter of the sheet rolls becomes smaller.
Laminating action varies according to the pinch angle existing when the sheets for laminating the paper and the paper to be laminated are pinched. That is, when the pinch angle is small, the adhesive layers of the sheets adhere to the surfaces of the paper upstream from a pinching point by the pinch rollers (upstream to the paper feed direction), so that the sheets and the paper adhere to each other before a pinching pressure is applied to them by pinch rollers. Therefore, problems occur that the sheets or the paper become wrinkled or air bubbles are bounded between the sheets and the paper.
On the other hand, when the pinch angle is too large, for example, approximately 90 degrees, a resistance of drawing the sheets from the sheet rolls increases, so that the laminating operation becomes difficult. Such a problem often arises when the sheet roll having a large diameter, that is, the sheet roll for laminating large sized paper, is used.
Incidentally, it has been desired that laminate targets having various widths would be laminated in the market. To respond to a demand to laminate an A3-size laminate target having a wide width, a laminating apparatus for laminating the A3-size laminate target (hereinafter referred to as a laminating apparatus for A3-size paper) has been developed.
However, in the laminating apparatus for A3-size paper, the width of the axial direction of the sheet roll for A3-size paper is larger than the width of the conventional sheet rolls for A4-size paper or A6-size paper. Further, the feed length of the sheet drawn from the sheet roll for A3-size paper for one lamination is normally longer than the feed length of the sheet drawn from the sheet roll for A4-size paper or A6-size paper. Therefore, the length of the sheet wound in the sheet roll for A3-size paper is longer than that in either sheet roll for A4-size paper or A6-size paper. In other words, a diameter of the sheet roll for A3-size paper is larger than that of either sheet roll for A4-size paper or A6-size paper.
Accordingly, in the sheet cassette for A3-size paper, the width of the axial direction of the sheet cassette, the thickness of the sheet cassette in the direction of the supply path, and the height of the sheet cassette in the direction perpendicular to the direction of the supply path were large compared with those in either sheet cassette for A4-size paper or A6-size paper.
Therefore, the width of the cassette acommodating portion in the direction perpendicular to the direction of the supply path and the thickness of the cassette acommodating portion in the direction of the supply path in the laminating apparatus for A3-size paper are large compared with those of the conventional cassette accommodating portion, so that neither sheet cassette for A4-size paper nor the sheet cassette for A6-size paper can be accommodated or secured in the cassette accommodating portion.
Further, as to the supply path for laminating a laminate target in the sheet cassette for A3-size paper, the diameter of the sheet roll for A3-size paper is larger than that of the sheet roll for either A4-size paper or A6-size paper, so that the laminate target insertion port and the laminate target feed-out portion of the sheet cassette for A3-size paper are located at a higher position compared with those of either sheet cassette for A4-size paper or A6-size paper.
Accordingly, when either sheet cassette for A4-size paper or A6-size paper is accommodated in the cassette accommodating portion in the laminating apparatus for A3-size paper as it is, the supply path is located at a lower position in the sheet supply unit. Therefore, a laminate target put on the laminate target supply unit (paper tray) could not pass either the laminate target insertion port or the laminate target feed-out port of the sheet cassettes for A4-size paper and A6-size paper.
For the reason described above, neither conventional sheet cassette for A4-size paper nor for A6-size paper can be set in the laminating apparatus for A3-size paper as it is.
Alternatively, in order to laminate a laminate target whose size is A4 or smaller in the laminating apparatus for A3-size paper, it is conceivable that there is a method by which a laminate target is laminated using the sheet cassette for A3-size paper whereby unnecessary portion of the sheet which exceeds a projection area of the laminate target is cut or a method whereby new sheet cassettes for A4-size paper and for A6-size per which can be mounted in the laminating apparatus for A3-size paper are developed.
However, in the method by which a laminate target is laminated using the sheet cassette for A3-size paper and an unnecessary portion of the sheet which exceeds a projection area of the laminate target is cut, an area corresponding to the unnecessary portion becomes large as the size of the laminate target becomes small, so that a yield of the sheet becomes low and it is inefficient.
Further, in the method by which new sheet cassettes for A4-size paper and A6-size paper which can be mounted in the laminating apparatus for A3-size paper are developed, there were problems that it takes a lot of trouble and time to develop such sheet cassettes and the operating costs become expensive because consumers have to buy the sheet cassettes for each laminating apparatus.
Therefore, the invention is made to solve the aforementioned problems of the prior art and it is an object of the invention to provide a laminating apparatus capable of maintaining laminating action substantially constantly regardless of the size of the diameter of sheet rolls and capable of laminating various sized papers (laminate targets).
According to a first aspect of the invention, a laminating apparatus may comprise a laminate target supply unit that supplies a laminate target, a sheet supply unit in which a pair of upper and lower sheets being wound in a roll shape are detachably mounted, and that supplies the pair of sheets, and a laminate processor that laminates the laminate target supplied from the laminate target supply unit with the pair of sheets supplied from the sheet supply unit while the laminate target is sandwiched between the pair of sheets and fed out as a laminated product, wherein a laminate processor including a pair of upper and lower pinch rollers that are rotatably disposed in the laminating processor, and a pair of upper and lower sheet guide portions disposed between both pinch rollers, and sides of drawing the sheets from the pair of sheet rolls, wherein the sheets are drawn from peripheries of the upper and lower sheet rolls that are apart from the center of each upper and lower sheet rolls in an upper and a lower directions so that outer surfaces of each sheet slide and contact at the sheet guide portions, the centers of each sheet roll are disposed at the positions that are apart from extension lines of sheet leading directions connecting a respective periphery of a pinching side of each pinch roller and slide contact portions of the sheet guides.
With this arrangement, the outer surfaces of the sheets drawn from the peripheries of each sheet roll are surely warped at the slide contact portions of the upper and lower guide portions and then are let to the pinching portion of the pinch rollers, which includes a certain pinch angle, along the lead lines of the sheets.
Therefore, regardless of the winding diameter size of the sheet roll in the pristine condition or the size change of the winding diameter through the use of the sheets, remarkable effects are produced such that the pinch angles become constant and the laminating action is maintained constant.
According to a second aspect of the invention, in the laminating apparatus of the first aspect of the invention, the center of the sheet roll is positioned so as to be apart from the sheet guide portions to a laminate target leading side in proportion to a size of the winding diameter of the sheet in a pristine condition. With this arrangement, as in the case where the sheet rolls are mounted using the sheet cassette, the pinch angles become constant and, thus, the laminating action is maintained constant regardless of the size of the initial winding diameter of the sheet rolls or the changes of the diameters of the sheet rolls through the use of the sheets.
According to a third aspect of the invention, in the laminating apparatus of the first aspect of the invention, a sheet cassette, in which the sheets wound in a roll shape are accommodated, is structured so as to be detachably mounted in the sheet supply unit and the sheet cassette is provided with the sheet guide portions. The sheet cassette accommodating sheet rolls having a large winding diameter in pristine condition and the sheet cassette accommodating sheet rolls having a small winding diameter in pristine condition can be disposed so as to produce the same laminating action on both sized sheet cassettes.
Further, according to a fourth aspect of the invention, in the laminating apparatus of the third aspect of the invention, a dimension of a feed direction of the laminate target in the sheet supply unit is formed to correspond to the sheet cassette accommodating the sheet having a winding large diameter, the sheet supply unit is structured so that an attachment can be mounted thereof, and a sheet cassette accommodating the sheet having a small winding diameter is detachably attached to the attachment at a position adjacent to the pinch rollers.
In addition to the effects obtained by the invention, the sheet cassette accommodating sheet rolls having a small winding diameter can be mounted in one laminating apparatus using the attachment, and thus an effect that the applicability of the laminating apparatus is expanded is produced.